(a) Field of the Invention
The present invention provides a digitally controlled switched-mode power supply, and more particularly provides a digitally controlled switched-mode power supply which is not limited to digital signals but also enables the input of analog signals.
(b) Description of the Prior Art
It can be said that modern technology continually strives for advancement, and there has been continuous progress in electric circuits from the large-scale electric circuits of old to the micro electric circuits of modern times, wherein analog control circuits were adopted for transmission in early electric circuits, until the present stage of advancement enabled digital control circuits to be adopted. Taking a power supply as an example, and referring to FIG. 1 and FIG. 2, which show a block diagram and a circuit diagram respectively of a switched-mode power supply of the prior art, and it can be clearly seen from the drawings that a control circuit 1 is provided with a rectifier unit 11. The rectifier unit 11 transmits a signal to a switching controller 13 through a voltage transformer unit 12, whereupon the switching controller 13 carries out a comparative analysis of the signal, and a frequency generator 131 produces a clock signal with a specific width from the aforementioned comparative signal, which is then output. Furthermore, an optical coupling unit 14 is disposed before the specific signal, and the optical coupling unit 14 is connected to an amplifier and feedback unit (voltage regulator) 15. The amplifier and feedback unit (voltage regulator) 15 is provided with the functionality to detect voltage, and immediately regulates the voltage when excessively high, while simultaneously controlling the size of the flow of current, thereby achieving a regulating objective, and enabling controlling the entire output structure, such as voltage.
However, the following problems and shortcomings are still in need of improvement when using the aforementioned switched-mode power supply of the prior art:
1. Because the control circuit 1 adopts an amplifier and feedback component (voltage regulator) (TL431), thus, it is unable to accurately control the system, such as the voltage state, and so on.
2. Power consumption of the control circuit 1 is considerably large, and is thus unable to achieve a power saving objective.
Hence, it is the strong desire of the inventor and manufacturers engaged in related art and purpose of the present invention to research, improve and resolve the problems and shortcomings of the aforementioned prior art.